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OBJECTIVE: Use of continuous glucose monitoring (CGM) has led to greater detection of hypoglycemia; the clinical significance of this is not fully understood. The Hypoglycaemia-Measurement, Thresholds and Impacts (Hypo-METRICS) study was designed to investigate the rates and duration of sensor-detected hypoglycemia (SDH) and their relationship with person-reported hypoglycemia (PRH) in people living with type 1 diabetes (T1D) and insulin-treated type 2 diabetes (T2D) with prior experience of hypoglycemia. RESEARCH DESIGN AND METHODS: We recruited 276 participants with T1D and 321 with T2D who wore a blinded CGM and recorded PRH in the Hypo-METRICS app over 10 weeks. Rates of SDH <70 mg/dL, SDH <54 mg/dL, and PRH were expressed as median episodes per week. Episodes of SDH were matched to episodes of PRH that occurred within 1 h. RESULTS: Median [interquartile range] rates of hypoglycemia were significantly higher in T1D versus T2D; for SDH <70 mg/dL (6.5 [3.8-10.4] vs. 2.1 [0.8-4.0]), SDH <54 mg/dL (1.2 [0.4-2.5] vs. 0.2 [0.0-0.5]), and PRH (3.9 [2.4-5.9] vs. 1.1 [0.5-2.0]). Overall, 65% of SDH <70 mg/dL was not associated with PRH, and 43% of PRH had no associated SDH. The median proportion of SDH associated with PRH in T1D was higher for SDH <70 mg/dL (40% vs. 22%) and SDH <54 mg/dL (47% vs. 25%) than in T2D. CONCLUSIONS: The novel findings are that at least half of CGM hypoglycemia is asymptomatic, even below 54 mg/dL, and many reported symptomatic hypoglycemia episodes happen above 70 mg/dL. In the clinical and research setting, these episodes cannot be used interchangeably, and both need to be recorded and addressed.

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AIMS/HYPOTHESIS: The aim of this work was to examine the impact of hypoglycaemia on daily functioning among adults with type 1 diabetes or insulin-treated type 2 diabetes, using the novel Hypo-METRICS app. METHODS: For 70 consecutive days, 594 adults (type 1 diabetes, n=274; type 2 diabetes, n=320) completed brief morning and evening Hypo-METRICS 'check-ins' about their experienced hypoglycaemia and daily functioning. Participants wore a blinded glucose sensor (i.e. data unavailable to the participants) for the study duration. Days and nights with or without person-reported hypoglycaemia (PRH) and/or sensor-detected hypoglycaemia (SDH) were compared using multilevel regression models. RESULTS: Participants submitted a mean ± SD of 86.3±12.5% morning and 90.8±10.7% evening check-ins. For both types of diabetes, SDH alone had no significant associations with the changes in daily functioning scores. However, daytime and night-time PRH (with or without SDH) were significantly associated with worsening of energy levels, mood, cognitive functioning, negative affect and fear of hypoglycaemia later that day or while asleep. In addition, night-time PRH (with or without SDH) was significantly associated with worsening of sleep quality (type 1 and type 2 diabetes) and memory (type 2 diabetes). Further, daytime PRH (with or without SDH), was associated with worsening of fear of hyperglycaemia while asleep (type 1 diabetes), memory (type 1 and type 2 diabetes) and social functioning (type 2 diabetes). CONCLUSIONS/INTERPRETATION: This prospective, real-world study reveals impact on several domains of daily functioning following PRH but not following SDH alone. These data suggest that the observed negative impact is mainly driven by subjective awareness of hypoglycaemia (i.e. PRH), through either symptoms or sensor alerts/readings and/or the need to take action to prevent or treat episodes.

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Introduction: This study examined associations between hypoglycemia awareness status and hypoglycemia symptoms reported in real-time using the novel Hypoglycaemia-MEasurement, ThResholds and ImpaCtS (Hypo-METRICS) smartphone application (app) among adults with insulin-treated type 1 (T1D) or type 2 diabetes (T2D). Methods: Adults who experienced at least one hypoglycemic episode in the previous 3 months were recruited to the Hypo-METRICS study. They prospectively reported hypoglycemia episodes using the app for 10 weeks. Any of eight hypoglycemia symptoms were considered present if intensity was rated between "A little bit" to "Very much" and absent if rated "Not at all." Associations between hypoglycemia awareness (as defined by Gold score) and hypoglycemia symptoms were modeled using mixed-effects binary logistic regression, adjusting for glucose monitoring method and diabetes duration. Results: Of 531 participants (48% T1D, 52% T2D), 45% were women, 91% white, and 59% used Flash or continuous glucose monitoring. Impaired awareness of hypoglycemia (IAH) was associated with lower odds of reporting autonomic symptoms than normal awareness of hypoglycemia (NAH) (T1D odds ratio [OR] 0.43 [95% confidence interval {CI} 0.25-0.73], P = 0.002); T2D OR 0.51 [95% CI 0.26-0.99], P = 0.048), with no differences in neuroglycopenic symptoms. In T1D, relative to NAH, IAH was associated with higher odds of reporting autonomic symptoms at a glucose concentration <54 than >70 mg/dL (OR 2.18 [95% CI 1.21-3.94], P = 0.010). Conclusion: The Hypo-METRICS app is sensitive to differences in hypoglycemia symptoms according to hypoglycemia awareness in both diabetes types. Given its high ecological validity and low recall bias, the app may be a useful tool in research and clinical settings. The clinical trial registration number is NCT04304963.

Asunto(s)

Automonitorización de la Glucosa Sanguínea , Diabetes Mellitus Tipo 1 , Diabetes Mellitus Tipo 2 , Hipoglucemia , Hipoglucemiantes , Insulina , Aplicaciones Móviles , Teléfono Inteligente , Humanos , Hipoglucemia/inducido químicamente , Femenino , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Diabetes Mellitus Tipo 2/complicaciones , Diabetes Mellitus Tipo 2/sangre , Masculino , Persona de Mediana Edad , Diabetes Mellitus Tipo 1/tratamiento farmacológico , Diabetes Mellitus Tipo 1/complicaciones , Diabetes Mellitus Tipo 1/sangre , Insulina/uso terapéutico , Insulina/administración & dosificación , Insulina/efectos adversos , Hipoglucemiantes/uso terapéutico , Hipoglucemiantes/efectos adversos , Adulto , Concienciación , Glucemia/análisis , Anciano , Estudios Prospectivos

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Introduction: Nocturnal hypoglycemia is generally calculated between 00:00 and 06:00. However, those hours may not accurately reflect sleeping patterns and it is unknown whether this leads to bias. We therefore compared hypoglycemia rates while asleep with those of clock-based nocturnal hypoglycemia in adults with type 1 diabetes (T1D) or insulin-treated type 2 diabetes (T2D). Methods: Participants from the Hypo-METRICS study wore a blinded continuous glucose monitor and a Fitbit Charge 4 activity monitor for 10 weeks. They recorded details of episodes of hypoglycemia using a smartphone app. Sensor-detected hypoglycemia (SDH) and person-reported hypoglycemia (PRH) were categorized as nocturnal (00:00-06:00 h) versus diurnal and while asleep versus awake defined by Fitbit sleeping intervals. Paired-sample Wilcoxon tests were used to examine the differences in hypoglycemia rates. Results: A total of 574 participants [47% T1D, 45% women, 89% white, median (interquartile range) age 56 (45-66) years, and hemoglobin A1c 7.3% (6.8-8.0)] were included. Median sleep duration was 6.1 h (5.2-6.8), bedtime and waking time ∼23:30 and 07:30, respectively. There were higher median weekly rates of SDH and PRH while asleep than clock-based nocturnal SDH and PRH among people with T1D, especially for SDH <70 mg/dL (1.7 vs. 1.4, P < 0.001). Higher weekly rates of SDH while asleep than nocturnal SDH were found among people with T2D, especially for SDH <70 mg/dL (0.8 vs. 0.7, P < 0.001). Conclusion: Using 00:00 to 06:00 as a proxy for sleeping hours may underestimate hypoglycemia while asleep. Future hypoglycemia research should consider the use of sleep trackers to record sleep and reflect hypoglycemia while asleep more accurately. The trial registration number is NCT04304963.

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Automonitorización de la Glucosa Sanguínea , Glucemia , Diabetes Mellitus Tipo 1 , Diabetes Mellitus Tipo 2 , Hipoglucemia , Sueño , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Glucemia/análisis , Ritmo Circadiano/fisiología , Diabetes Mellitus Tipo 1/sangre , Diabetes Mellitus Tipo 1/complicaciones , Diabetes Mellitus Tipo 2/complicaciones , Diabetes Mellitus Tipo 2/sangre , Hipoglucemia/sangre , Hipoglucemiantes/uso terapéutico , Insulina/administración & dosificación , Insulina/uso terapéutico , Sueño/fisiología

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INTRODUCTION: Hypoglycaemia is a significant burden to people living with diabetes and an impediment to achieving optimal glycaemic outcomes. The use of continuous glucose monitoring (CGM) has improved the capacity to assess duration and level of hypoglycaemia. The personal impact of sensor-detected hypoglycaemia (SDH) is unclear. Hypo-METRICS is an observational study designed to define the threshold and duration of sensor glucose that provides the optimal sensitivity and specificity for events that people living with diabetes experience as hypoglycaemia. METHODS: We will recruit 600 participants: 350 with insulin-treated type 2 diabetes, 200 with type 1 diabetes and awareness of hypoglycaemia and 50 with type 1 diabetes and impaired awareness of hypoglycaemia who have recent experience of hypoglycaemia. Participants will wear a blinded CGM device and an actigraphy monitor to differentiate awake and sleep times for 10 weeks. Participants will be asked to complete three short surveys each day using a bespoke mobile phone app, a technique known as ecological momentary assessment. Participants will also record all episodes of self-detected hypoglycaemia on the mobile app. We will use particle Markov chain Monte Carlo optimization to identify the optimal threshold and duration of SDH that have optimum sensitivity and specificity for detecting patient-reported hypoglycaemia. Key secondary objectives include measuring the impact of symptomatic and asymptomatic SDH on daily functioning and health economic outcomes. ETHICS AND DISSEMINATION: The protocol was approved by local ethical boards in all participating centres. Study results will be shared with participants, in peer-reviewed journal publications and conference presentations.

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Diabetes Mellitus Tipo 1 , Diabetes Mellitus Tipo 2 , Hipoglucemia , Benchmarking , Glucemia , Automonitorización de la Glucosa Sanguínea/métodos , Diabetes Mellitus Tipo 1/complicaciones , Diabetes Mellitus Tipo 1/tratamiento farmacológico , Diabetes Mellitus Tipo 2/complicaciones , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Hemoglobina Glucada/análisis , Humanos , Hipoglucemia/diagnóstico , Hipoglucemiantes/uso terapéutico , Estudios Observacionales como Asunto , Calidad de Vida

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INTRODUCTION: Hypoglycaemia is a frequent adverse event and major barrier for achieving optimal blood glucose levels in people with type 1 or type 2 diabetes using insulin. The Hypo-RESOLVE (Hypoglycaemia-Redefining SOLutions for better liVEs) consortium aims to further our understanding of the day-to-day impact of hypoglycaemia. The Hypo-METRICS (Hypoglycaemia-MEasurement, ThResholds and ImpaCtS) application (app) is a novel app for smartphones. This app is developed as part of the Hypo-RESOLVE project, using ecological momentary assessment methods that will minimise recall bias and allow for robust investigation of the day-to-day impact of hypoglycaemia. In this paper, the development and planned psychometric analyses of the app are described. METHODS AND ANALYSIS: The three phases of development of the Hypo-METRICS app are: (1) establish a working group-comprising diabetologists, psychologists and people with diabetes-to define the problem and identify relevant areas of daily functioning; (2) develop app items, with user-testing, and implement into the app platform; and (3) plan a large-scale, multicountry study including interviews with users and psychometric validation. The app includes 7 modules (29 unique items) assessing: self-report of hypoglycaemic episodes (during the day and night, respectively), sleep quality, well-being/cognitive function, social interactions, fear of hypoglycaemia/hyperglycaemia and work/productivity. The app is designed for use within three fixed time intervals per day (morning, afternoon and evening). The first version was released mid-2020 for use (in conjunction with continuous glucose monitoring and activity tracking) in the Hypo-METRICS study; an international observational longitudinal study. As part of this study, semistructured user-experience interviews and psychometric analyses will be conducted. ETHICS AND DISSEMINATION: Use of the novel Hypo-METRICS app in a multicountry clinical study has received ethical approval in each of the five countries involved (Oxford B Research Ethics Committee, CMO Region Arnhem-Nijmegen, Ethikkommission der Medizinischen Universität Graz, Videnskabsetisk Komite for Region Hovedstaden and the Comite Die Protection Des Personnes SUD Mediterranne IV). The results from the study will be published in peer review journals and presented at national and international conferences. TRIAL REGISTRATION NUMBER: NCT04304963.

Asunto(s)

Diabetes Mellitus Tipo 1 , Diabetes Mellitus Tipo 2 , Hipoglucemia , Adulto , Benchmarking , Glucemia , Automonitorización de la Glucosa Sanguínea , Diabetes Mellitus Tipo 1/complicaciones , Diabetes Mellitus Tipo 1/tratamiento farmacológico , Diabetes Mellitus Tipo 1/psicología , Diabetes Mellitus Tipo 2/complicaciones , Humanos , Hipoglucemia/prevención & control , Hipoglucemiantes , Estudios Longitudinales

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BACKGROUND AND OBJECTIVE: As continuous glucose monitoring (CGM) becomes common in research and clinical practice, there is a need to understand how CGM-based hypoglycemia relates to hypoglycemia episodes defined conventionally as patient reported hypoglycemia (PRH). Data show that CGM identify many episodes of low interstitial glucose (LIG) that are not experienced by patients, and so the aim of this study is to use different PRH simulations to optimize CGM parameters of threshold (h) and duration (d) to provide the best PRH detection performance. METHODS: The algorithm uses particle Markov chain Monte Carlo optimization to identify the optimal h and d which maximize an objective function for detecting PRH. We tested our algorithm by creating three different cases of PRH simulations. RESULTS: We added three types of simulated PRH events to 10 weeks of anonymized CGM data from 96 type 1 diabetes people to see if the algorithm can detect the optimal parameters set out in the simulations. In simulation 1, we changed the locations of PRHs with respect to LIG episodes in the CGM signal to simulate random optimal LIG parameters for every individual. In simulation 2, the PRHs are CGM glucose <3.9 mmol/L followed by at least 20 min of rise > 0.11 mmol/L/min. Simulation 3 is like simulation 2 but with glucose threshold of 3.0 mmol/L. The median [interquartile range] of deviation between the optimized (found by the algorithm) and the optimal (known) h and d are -0.07% [-0.4, 1.9] and -1.3% [-5.9, 6.8], respectively across the subjects for simulation 1. The mean [min max] of the optimized LIG parameters are h = 3.8 [3.7, 3.8] mmol/L and d = 12 [10, 14] min for simulation 2 and they are h = 3.0 [2.9, 3] mmol/L and d = 10 [8, 14] min for simulation 3 across a 10-fold cross validation. CONCLUSIONS: This work demonstrates the feasibility of the algorithm to find the best-fit definition of CGM-based hypoglycemia for PRH detection. In a prospective clinical study collecting CGM and PRH, the current algorithm will be used to optimize the definition of hypoglycemia with respect to PRH with the ambition of using the resulted definition as a surrogate for PRH in clinical practice.

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Diabetes Mellitus Tipo 1 , Hipoglucemia , Glucemia , Automonitorización de la Glucosa Sanguínea , Humanos , Hipoglucemia/diagnóstico , Estudios Prospectivos

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OBJECTIVE: Stroke is one of the main causes of disability and the second common cause of mortality in the world. Stroke causes relatively permanent motor defects, including balance disorder, and thus affects an individual's functional capacity and independence. Many clinical types of research have been conducted to evaluate the effect of functional electrical stimulation (FES) on balance in post-stroke patients. The objective of this study was to systematically review the effect of functional electrical stimulation (FES) on balance as compared to conventional therapy alone in post-stroke. METHODS: The databases of Google Scholar, PubMed, Scopus, ScienceDirect and ProQuest were searched using selected keywords. The randomized controlled trials were searched for published original articles before February 2019 in English language and included if they assessed the effect of FES on balance ability compared to conventional therapy alone in adult post-stroke. The Physiotherapy Evidence Database (PEDro) scale was used to assess the methodological quality. RESULTS: Nine papers were included in this review (median PEDro scale =7/11). The total number of participants in this review study was 255. The age of participants ranged from 20 to 80 years. Stroke patients were in chronic phase (n = 5) and in subacute phase (n = 4). various parameters, including the target muscles, the treatment time per session (20 min-2 h), number of treatment sessions (12-48) and FES frequency (25-40 Hz), were assessed. Among the studies, significant between-group improvement favoring FES in combination with conventional therapy was found on the Berg Balance Scale (n = 7) and Timed Up and Go Scale (n = 4) when compared to conventional therapy alone. There was no adverse effect reported by any studies. CONCLUSION: FES was reported to be more beneficial in balance improvement among stroke patients when combined with conventional balance therapy. The studies were limited by low-powered, small sample sizes ranging from 9 to 48, and lack of blinding, and reporting of missing data.

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Terapia por Estimulación Eléctrica , Músculo Esquelético/inervación , Equilibrio Postural , Accidente Cerebrovascular/terapia , Adulto , Anciano , Anciano de 80 o más Años , Evaluación de la Discapacidad , Terapia por Estimulación Eléctrica/efectos adversos , Femenino , Estado Funcional , Humanos , Extremidad Inferior , Masculino , Persona de Mediana Edad , Recuperación de la Función , Accidente Cerebrovascular/diagnóstico , Accidente Cerebrovascular/fisiopatología , Resultado del Tratamiento , Adulto Joven

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Acinetobacter baumannii, one of the most life-threatening nosocomial drug-resistant pathogens, imposes high morbidity and mortality rates, thus highlighting immunization-based treatments or prevention measures. The selection of appropriate antigens can elicit protective immunity. The gene encoding a fimbrial protein introduced via reverse vaccinology was cloned, expressed and evaluated for immunogenicity in a murine model. Mice immunized with the recombinant protein were challenged with A. baumannii ATCC 19606. Adherence to A549 cell line of specific anti-sera treated A. baumannii was also assessed. Passive immunity was evaluated in a murine pneumonia model. Indirect ELISA showed a high specific antibody titre. Adherence of A. baumannii to A549 cell line decreased by 40% after incubation with 1:250 dilution of specific anti-sera. All the actively immunized mice survived. Bacterial load in the spleen and liver of the immunized mice was 3-fold lower than those of the control. The number of bacteria in the lungs of passively immunized mice was about 6-fold lower than the control mice. The fimbrial protein could be considered as a promising protective immunogen against A. baumannii.

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Infecciones por Acinetobacter/prevención & control , Acinetobacter baumannii/inmunología , Proteínas de la Membrana Bacteriana Externa/inmunología , Vacunas Bacterianas/inmunología , Infección Hospitalaria/prevención & control , Fimbrias Bacterianas/inmunología , Inmunización , Células A549 , Animales , Adhesión Bacteriana , Humanos , Ratones , Ratones Endogámicos BALB C

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Background: The aim was to compare the accuracy of the Dexcom® G4 Platinum continuous glucose monitor (CGM) sensor inserted on the upper arm and the abdomen in adults. Methods: Fourteen adults with type 1 diabetes wore two CGMs, one placed on the upper arm and one placed on the abdomen. Three in-clinic visits of 5 h with YSI (2300 STAT, Yellow Springs Instrument) measurements as comparator were performed. Each visit was followed by 4 days with seven-point self-monitoring of blood glucose (SMBG) in free-living conditions. Accuracy analyses on the paired CGM-YSI and CGM-SMBG measurements of the two CGM sensors were performed. Results: Using YSI as comparator, the overall Mean Absolute Relative Difference (MARD) for the CGMabd was 12.3% and CGMarm was 12.0%. The percentage of the CGM measurements in zone A of Clarke error grid analysis for the CGMabd was 85.6% and CGMarm was 86.0%. The hypoglycemia sensitivity for the CGMabd and CGMarm was 69.3%. Using SMBG as comparator, the overall MARD for the CGMabd was 12.5% and CGMarm was 12.0%. The percentage of the CGM measurements in zone A for the CGMabd was 84.1% and the CGMarm was 85.0%. The hypoglycemia sensitivity for the CGMabd was 60.0% and the CGMarm was 71.1%. All the P-values from the comparisons between the accuracy of CGMabd and CGMarm were >0.05. Conclusion: The accuracy of a Dexcom G4 Platinum CGM sensor placed on the upper arm was not different from the accuracy of the sensor placed on the abdomen in adults with type 1 diabetes.

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Automonitorización de la Glucosa Sanguínea/métodos , Glucemia/análisis , Diabetes Mellitus Tipo 1/sangre , Abdomen , Adulto , Anciano , Brazo , Automonitorización de la Glucosa Sanguínea/instrumentación , Femenino , Humanos , Sistemas de Infusión de Insulina , Masculino , Persona de Mediana Edad , Reproducibilidad de los Resultados , Adulto Joven

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The purpose of this study is to compare the performance of three nonlinear filters in online drift detection of continuous glucose monitors. The nonlinear filters are the extended Kalman filter (EKF), the unscented Kalman filter (UKF), and the particle filter (PF). They are all based on a nonlinear model of the glucose-insulin dynamics in people with type 1 diabetes. Drift is modelled by a Gaussian random walk and is detected based on the statistical tests of the 90-min prediction residuals of the filters. The unscented Kalman filter had the highest average F score of 85.9%, and the smallest average detection delay of 84.1%, with the average detection sensitivity of 82.6%, and average specificity of 91.0%.

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Análisis Químico de la Sangre/métodos , Glucemia/análisis , Modelos Biológicos , Dinámicas no Lineales , Análisis Químico de la Sangre/instrumentación , Humanos , Distribución Normal , Procesamiento de Señales Asistido por Computador

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BACKGROUND: The use of continuous glucose monitoring (CGM) in clinical decision making in diabetes could be limited by the inaccuracy of CGM data when compared to plasma glucose measurements. The aim of the present study is to investigate the impact of CGM numerical accuracy on the precision of diabetes treatment adjustments. METHOD: CGM profiles with maximum 5-day duration from 12 patients with type 1 diabetes treated with a basal-bolus insulin regimen were processed by 2 CGM algorithms, with the accuracy of algorithm 2 being higher than the accuracy of algorithm 1, using the median absolute relative difference (MARD) as the measure of accuracy. During 2 separate and similar occasions over a 1-month interval, 3 clinicians reviewed the processed CGM profiles, and adjusted the dose level of basal and prandial insulin. The precision of the dosage adjustments were defined in terms of the interclinician agreement and the intraclinician reproducibility of the decisions. The Cohen's kappa coefficient was used to assess the precision of the decisions. The study was based on retrospective and blind CGM data. RESULTS: For the interclinician agreement, in the first occasion, the kappa of algorithm 1 was .32, and that of algorithm 2 was .36. For the interclinician agreement, in the second occasion, the kappas of algorithms 1 and 2 were .17 and .22, respectively. For the intraclinician reproducibility of the decisions, the kappas of algorithm 1 were .35, .22, and .80 and the kappas of algorithm 2 were .44, .52, and .32, for the 3 clinicians, respectively. For the interclinician agreement, the relative kappa change from algorithm 1 to algorithm 2 was 86.06%, and for the intraclinician reproducibility, the relative kappa change from algorithm 1 to algorithm 2 was 53.99%. CONCLUSIONS: Results indicated that the accuracy of CGM algorithms might potentially affect the precision of the CGM-based insulin adjustments for type 1 diabetes patients. However, a larger study with several clinical centers, with higher number of clinicians and patients is required to validate the impact of CGM accuracy on decisions precision.

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Automonitorización de la Glucosa Sanguínea/métodos , Glucemia/análisis , Toma de Decisiones Clínicas , Diabetes Mellitus Tipo 1/sangre , Algoritmos , Diabetes Mellitus Tipo 1/tratamiento farmacológico , Femenino , Humanos , Hipoglucemiantes/administración & dosificación , Hipoglucemiantes/uso terapéutico , Insulina/administración & dosificación , Insulina/uso terapéutico , Persona de Mediana Edad , Proyectos Piloto , Estudios Retrospectivos

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BACKGROUND: The purpose of this study was to evaluate the performance of a new continuous glucose monitoring (CGM) calibration algorithm and to compare it with the Guardian(®) REAL-Time (RT) (Medtronic Diabetes, Northridge, CA) calibration algorithm in hypoglycemia. SUBJECTS AND METHODS: CGM data were obtained from 10 type 1 diabetes patients undergoing insulin-induced hypoglycemia. Data were obtained in two separate sessions using the Guardian RT CGM device. Data from the same CGM sensor were calibrated by two different algorithms: the Guardian RT algorithm and a new calibration algorithm. The accuracy of the two algorithms was compared using four performance metrics. RESULTS: The median (mean) of absolute relative deviation in the whole range of plasma glucose was 20.2% (32.1%) for the Guardian RT calibration and 17.4% (25.9%) for the new calibration algorithm. The mean (SD) sample-based sensitivity for the hypoglycemic threshold of 70 mg/dL was 31% (33%) for the Guardian RT algorithm and 70% (33%) for the new algorithm. The mean (SD) sample-based specificity at the same hypoglycemic threshold was 95% (8%) for the Guardian RT algorithm and 90% (16%) for the new calibration algorithm. The sensitivity of the event-based hypoglycemia detection for the hypoglycemic threshold of 70 mg/dL was 61% for the Guardian RT calibration and 89% for the new calibration algorithm. Application of the new calibration caused one false-positive instance for the event-based hypoglycemia detection, whereas the Guardian RT caused no false-positive instances. The overestimation of plasma glucose by CGM was corrected from 33.2 mg/dL in the Guardian RT algorithm to 21.9 mg/dL in the new calibration algorithm. CONCLUSIONS: The results suggest that the new algorithm may reduce the inaccuracy of Guardian RT CGM system within the hypoglycemic range; however, data from a larger number of patients are required to compare the clinical reliability of the two algorithms.

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Técnicas Biosensibles , Glucemia/metabolismo , Diabetes Mellitus Tipo 1/sangre , Hipoglucemia/prevención & control , Hipoglucemiantes/administración & dosificación , Monitoreo Ambulatorio , Adulto , Algoritmos , Automonitorización de la Glucosa Sanguínea , Calibración , Diabetes Mellitus Tipo 1/tratamiento farmacológico , Femenino , Humanos , Hipoglucemia/sangre , Masculino , Ensayo de Materiales , Reproducibilidad de los Resultados , Sensibilidad y Especificidad

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The purpose of this study was to investigate the effect of using a 1-point calibration approach instead of a 2-point calibration approach on the accuracy of a continuous glucose monitoring (CGM) algorithm. A previously published real-time CGM algorithm was compared with its updated version, which used a 1-point calibration instead of a 2-point calibration. In addition, the contribution of the corrective intercept (CI) to the calibration performance was assessed. Finally, the sensor background current was estimated real-time and retrospectively. The study was performed on 132 type 1 diabetes patients. Replacing the 2-point calibration with the 1-point calibration improved the CGM accuracy, with the greatest improvement achieved in hypoglycemia (18.4% median absolute relative differences [MARD] in hypoglycemia for the 2-point calibration, and 12.1% MARD in hypoglycemia for the 1-point calibration). Using 1-point calibration increased the percentage of sensor readings in zone A+B of the Clarke error grid analysis (EGA) in the full glycemic range, and also enhanced hypoglycemia sensitivity. Exclusion of CI from calibration reduced hypoglycemia accuracy, while slightly increased euglycemia accuracy. Both real-time and retrospective estimation of the sensor background current suggest that the background current can be considered zero in the calibration of the SCGM1 sensor. The sensor readings calibrated with the 1-point calibration approach indicated to have higher accuracy than those calibrated with the 2-point calibration approach.

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Algoritmos , Automonitorización de la Glucosa Sanguínea/métodos , Adulto , Anciano , Glucemia/análisis , Automonitorización de la Glucosa Sanguínea/instrumentación , Automonitorización de la Glucosa Sanguínea/estadística & datos numéricos , Calibración , Femenino , Humanos , Hipoglucemia/sangre , Masculino , Microdiálisis , Persona de Mediana Edad , Reproducibilidad de los Resultados , Estudios Retrospectivos

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BACKGROUND: People with type 1 diabetes (T1D) are unable to produce insulin and thus rely on exogenous supply to lower their blood glucose. Studies have shown that intensive insulin therapy reduces the risk of late-diabetic complications by lowering average blood glucose. However, the therapy leads to increased incidence of hypoglycemia. Although inaccurate, professional continuous glucose monitoring (PCGM) can be used to identify hypoglycemic events, which can be useful for adjusting glucose-regulating factors. New pattern classification approaches based on identifying hypoglycemic events through retrospective analysis of PCGM data have shown promising results. The aim of this study was to evaluate a new pattern classification approach by comparing the performance with a newly developed PCGM calibration algorithm. METHODS: Ten male subjects with T1D were recruited and monitored with PCGM and self-monitoring blood glucose during insulin-induced hypoglycemia. A total of 19 hypoglycemic events occurred during the sessions. RESULTS: The pattern classification algorithm detected 19/19 hypoglycemic events with 1 false positive, while the PCGM with the new calibration algorithm detected 17/19 events with 2 false positives. CONCLUSIONS: We can conclude that even after the introduction of new calibration algorithms, the pattern classification approach is still a valuable addition for improving retrospective hypoglycemia detection using PCGM.

RESUMEN

BACKGROUND: The deviation of continuous subcutaneous glucose monitoring (CGM) data from reference blood glucose measurements is substantial, and adequate signal processing is required to reduce the discrepancy between subcutaneous glucose and blood glucose values. The purpose of this study was to develop a multistep algorithm for the processing and calibration of continuous subcutaneous glucose monitoring data with high accuracy and short delay. Algorithm PRESENTATION: The algorithm comprises three steps: rate-limiting filtering, selective smoothing, and robust calibration. Initially, the algorithm detects nonphysiological glucose rate-of-change and corrects it with a weighted local polynomial. Noisy signal parts that require smoothing are then detected based on zero crossing count of the sensor signal first-order differences, and an exponentially weighted moving average smooths the noisy parts of the signal afterward. Finally, calibration is performed using a first-order polynomial as the conversion function, with coefficients being estimated using robust regression with a bi-square weight function. ALGORITHM PERFORMANCE: The performance of the algorithm was evaluated on 16 patients with type 1 diabetes mellitus. To compare the algorithm with state-of-the-art CGM data denoising and calibration, the rate-limiting filter and selective smoothing were replaced with an adaptive Kalman filter, and the calibration method was replaced with the calibration algorithm presented in one of the Medtronic (Northridge, CA) CGM patents. The median (mean) of the absolute relative deviation (ARD) of the sensor glucose values processed by the newly developed algorithm from capillary reference blood glucose measurements was 14.8% (22.6%), 10.6% (14.6%), and 8.9% (11.7%) in hypoglycemia, euglycemia, and hyperglycemia, respectively, whereas for the alternative algorithm, the median (mean) was 22.2% (26.9%), 12.1% (15.9%), and 8.8 (11.3%), respectively. The median (mean) ARD in all ranges was 10.3% (14.7%) for the new algorithm and 11.5% (15.8%) for the alternative algorithm. The new algorithm had an average delay of 2.1 min across the patients, and the alternative algorithm had an average delay of 2.9 min. CONCLUSIONS: The presented algorithm may increase the accuracy of CGM data.

Asunto(s)

Algoritmos , Técnicas Biosensibles/métodos , Glucemia/metabolismo , Calibración , Diabetes Mellitus Tipo 1/sangre , Microdiálisis , Monitoreo Fisiológico , Adulto , Automonitorización de la Glucosa Sanguínea , Dinamarca , Femenino , Humanos , Masculino , Monitoreo Fisiológico/instrumentación , Monitoreo Fisiológico/métodos , Reproducibilidad de los Resultados , Factores de Tiempo

RESUMEN

BACKGROUND: An important task in diabetes management is detection of hypoglycemia. Professional continuous glucose monitoring (CGM), which produces a glucose reading every 5 min, is a powerful tool for retrospective identification of unrecognized hypoglycemia. Unfortunately, CGM devices tend to be inaccurate, especially in the hypoglycemic range, which limits their applicability for hypoglycemia detection. The objective of this study was to develop an automated pattern recognition algorithm to detect hypoglycemic events in retrospective, professional CGM. METHOD: Continuous glucose monitoring and plasma glucose (PG) readings were obtained from 17 data sets of 10 type 1 diabetes patients undergoing insulin-induced hypoglycemia. The CGM readings were automatically classified into a hypoglycemic group and a nonhypoglycemic group on the basis of different features from CGM readings and insulin injection. The classification was evaluated by comparing the automated classification with PG using sample-based and event-based sensitivity and specificity measures. RESULTS: With an event-based sensitivity of 100%, the algorithm produced only one false hypoglycemia detection. The sample-based sensitivity and specificity levels were 78% and 96%, respectively. CONCLUSIONS: The automated pattern recognition algorithm provides a new approach for detecting unrecognized hypoglycemic events in professional CGM data. The tool may assist physicians and diabetologists in conducting a more thorough evaluation of the diabetes patient's glycemic control and in initiating necessary measures for improving glycemic control.

Asunto(s)

Algoritmos , Glucemia/análisis , Diabetes Mellitus Tipo 1/sangre , Hipoglucemia/diagnóstico , Adulto , Automatización , Automonitorización de la Glucosa Sanguínea , Humanos , Hipoglucemia/sangre , Masculino , Persona de Mediana Edad , Monitoreo Fisiológico , Estudios Retrospectivos , Sensibilidad y Especificidad

RESUMEN

BACKGROUND: Speech production and speech phonetic features gradually improve in children by obtaining audio feedback after cochlear implantation or using hearing aids. The aim of this study was to develop and evaluate automated classification of voice disorder in children with cochlear implantation and hearing aids. METHODS: We considered 4 disorder categories in children's voice using the following definitions: Level_1: Children who produce spontaneous phonation and use words spontaneously and imitatively. Level_2: Children, who produce spontaneous phonation, use words spontaneously and make short sentences imitatively. Level_3: Children, who produce spontaneous phonations, use words and arbitrary sentences spontaneously. Level_4: Normal children without any hearing loss background. Thirty Persian children participated in the study, including six children in each level from one to three and 12 children in level four. Voice samples of five isolated Persian words "mashin", "mar", "moosh", "gav" and "mouz" were analyzed. Four levels of the voice quality were considered, the higher the level the less significant the speech disorder. "Frame-based" and "word-based" features were extracted from voice signals. The frame-based features include intensity, fundamental frequency, formants, nasality and approximate entropy and word-based features include phase space features and wavelet coefficients. For frame-based features, hidden Markov models were used as classifiers and for word-based features, neural network was used. RESULTS: After Classifiers fusion with three methods: Majority Voting Rule, Linear Combination and Stacked fusion, the best classification rates were obtained using frame-based and word-based features with MVR rule (level 1:100%, level 2: 93.75%, level 3: 100%, level 4: 94%). CONCLUSIONS: Result of this study may help speech pathologists follow up voice disorder recovery in children with cochlear implantation or hearing aid who are in the same age range.

Asunto(s)

Clasificación/métodos , Implantación Coclear , Audífonos , Trastornos de la Voz/clasificación , Trastornos de la Voz/cirugía , Niño , Preescolar , Femenino , Pérdida Auditiva/complicaciones , Pérdida Auditiva/fisiopatología , Humanos , Lenguaje , Masculino , Fonación/fisiología , Voz/fisiología , Trastornos de la Voz/complicaciones , Trastornos de la Voz/fisiopatología